Diagnostic & Laboratory Core (Core D) To administer disease- and patient-specific care, accurate and rapid diagnosis of pediatric cancer is critical. The core includes the clinical laboratories in Uganda and Malawi, which will provide histological review, immunohistochemistry (IHC), and flow cytometry for prospective patients. Laboratory testing to monitor patients (CBCs, chemistry) will also be performed in these laboratories, as required for clinical care. Enhancements will be made to test the feasibility of using standardized diagnostic algorithms across multiple sites and implementing virtual pathology for central review, in preparation for a larger LMIC network in Africa. Centralized pathology review, especially for difficult to diagnose cases, is imperative for large-scale projects, such as those proposed by the Consortium. Due to lack of access to immunohistochemistry (IHC) and cytohistological review, misclassification of NHLs is common in SSA. This is even more critical in the HIV setting where the clinical and pathology characteristics of NHL are atypical e.g. high-grade B-cell NHL intermediate between DLBCL and BL are thought to be more prevalent. Further, non-cutaneous cases of Kaposi's sarcoma (KS) can be difficult to diagnose. The pathology services offered by this Core, and the improvements made to the algorithm over the course of the funding period, will greatly enhance the ability to more precisely diagnosis pediatric cancer diagnosis in the LMICs. The core will also provide oversight of sample processing, storage, and shipping for the research studies included in the proposal. In our experience, centralized processing of biospecimens ensures that they are processed according to appropriate standardized protocols, which minimizes unwanted variability when the samples are later analyzed. The responsibilities of the Diagnostic & Laboratory Core (Core D) include support for the processing of all biospecimens generated from the Projects and for implementing improvements in the pediatric cancer diagnosis algorithm at the SSA sites To accomplish these objectives, the Aims of the Diagnostic & Laboratory Core are: 1. To assist with the appropriate collection, processing, storage, and shipping of all biospecimens 2. To perform routine histologic review, immunohistochemistry, and flow cytometry of pediatric cancer cases for clinical diagnosis and laboratory testing for the ongoing monitoring of patients 3. To support the implementation, training, and coordination of central pathology review utilizing a virtual pathology network 4. To implement enhancements to clinical diagnostic algorithms by supporting onsite validation and training on additional methodologies 5. To assist the Developmental Core (Core B) in the education of additional pathologists and laboratory